Canadian Solar Wins Patent Dispute: Trina Solar’s TOPCon Patents Invalidated

In a significant development for the global solar industry, Canadian Solar has secured a major victory in its intellectual property dispute with Trina Solar. On April 17, 2026, the U.S. Patent Trial and Appeal Board (PTAB) issued final written decisions invalidating all claims of two key patents related to TOPCon solar cell technology that Trina Solar had asserted against its rival.

This ruling marks a critical turning point in the ongoing legal battles between two of the world’s leading solar module manufacturers and reinforces Canadian Solar’s position in the highly competitive market for next-generation solar technology.

Understanding the Canadian Solar patent win

The dispute centered on two patents that Trina Solar leveraged in a U.S. District Court infringement complaint filed against Canadian Solar subsidiaries in October 2024. In response, Canadian Solar challenged the validity of these patents directly with the PTAB.

The board’s decision to invalidate all claims of the patents in question effectively nullifies the basis of Trina’s infringement lawsuit in the U.S. Canadian Solar announced the outcome as a validation of its robust intellectual property defenses and its long-standing commitment to independent research and development.

The Technology at Stake: TOPCon

The patents in question relate to Tunnel Oxide Passivated Contact (TOPCon) technology, a leading-edge solar cell architecture. TOPCon cells feature an ultra-thin tunnel oxide layer and a layer of highly doped polysilicon, which work together to reduce energy losses from recombination. This advanced design significantly boosts solar cell efficiency, making it a crucial area of innovation and competition among photovoltaic (PV) manufacturers. As the industry pushes the boundaries of solar efficiency, control over foundational TOPCon IP has become increasingly contentious.

Broader Context of the IP Battle

This U.S. ruling is a key event in a wider landscape of legal disputes between the two solar giants. While Canadian Solar has prevailed in this U.S. case, it is still facing a lawsuit from Trina in China. Filed in February 2025 at the Jiangsu High People’s Court, that case alleges infringement of two different TOPCon-related patents and seeks substantial damages.

The PTAB’s decision is consistent with other recent findings. In a related matter, the board also deemed portions of other Trina TOPCon patents to be unpatentable, which cleared both Canadian Solar and Runergy of separate infringement claims. This series of rulings strengthens the position of companies defending against Trina’s patent assertions in the United States.

For Canadian Solar, this victory eliminates a significant patent risk for its subsidiaries operating in the U.S. market. More broadly, it underscores the fierce competition and the critical role of intellectual property in the rapidly evolving solar technology sector, particularly as companies vie for dominance in the high-efficiency TOPCon space.